It's not a question of efficiency. My figures assume 100%, which is certainly too optimistic. No, it's about the energy in any reasonably home-sized system is

It's not a question of efficiency. My figures assume 100%, which is certainly too optimistic. No, it's about the energy in any reasonably home-sized system is way too small. About one or two AAA batteries' worth. Though industrial-sized systems can be much better, they too are under-powered, against our needs. Except pumped-hydro.